Member Site Core Abstract NRG Oncology (NRG) has established a large and diverse membership that includes 220 Tier 1 (Main Members) and 1188 Tier 2 enrolling sites. NRG Main Members and affiliates are located in all 50 states, Washington, DC, and Puerto Rico. There are 16 Canadian Main Members and 12 Non-North American Main Members located in 8 countries. NRG Oncology has the largest membership base of the groups in the NCI National Clinical Trials Network (NCTN), and NRG members also contribute the highest percentage of patients to the NCTN. For the period of March 1, 2014, through August 31, 2017, NRG trial accrual plus accrual to other NCTN group trials credited to NRG by its members represents approximately a third of the total NCTN accrual for that grant period. Of the 9,000 American patients enrolled on NRG trials during this time period, 12.7% self-identified as of African descent, 8.0% as Hispanic or Latino, and 1.3% as Native Hawaiian, other Pacific Islander, Native American, or Alaska native.. NRG has developed an audit program which is in compliance with the guidelines established by the NCI's Clinical Trials Monitoring Branch (CTMB). In addition, NRG carefully evaluates protocol accrual and data quality, a practice which enables the group to identify and intervene when underperforming centers are identified. NRG has developed a variety of accrual enhancement efforts including: the NRG Protocol Support Committee that reviews all proposed protocols relative to nursing and non-nursing matters; the NRG Health Disparities Committee whose primary aim is to increase enrollment of underrepresented populations to NRG trials; the Communications Committee which provides updates to the NRG members and general public promoting NRG activities and trials; the Center for Innovation in Radiation Oncology (CIRO) which assists NRG members with radiotherapy and imaging quality assurance process, including site qualification, credentialing and case reviews; and a Toll-Free 800 Line available for NRG members to obtain answers to protocol related questions. NRG cancer disease site committees have developed successful programs for patients with rare tumors and trials that provide an opportunity to enroll adolescent and young adult patients.